# if

x=86
if x<60:
    print("不及格")
elif x<70:
    print("及格")
elif x<90:
    print("中等")
else:
    print("优秀")

2<5
2>5
2==5

not True
not False
not 0
not 1
not 2
not 'abc'
not ''

0 and 2     #返回0，and和or同java一样
2 and []    #[]
2 and 5     #5
5 and 2     #2

0 or 2      #2
2 or []     #[]
[] or {}    #{}

x=1
y=2
a = x if x>y else y #2
a

x=5
y=10
a=[x,y][x<y]
a                   #10